3D Printing in Space: ISS Crew Successfully Produces First Metal Component

A 3D printer on the International Space Station made the first metal part ever created in space. With this technology, astronauts can print tools and parts directly in orbit in the future.

Is 3D Metal Printing Possible In Microgravity?

The project team intends to answer this and many other questions. The consortium, which implements the project under the programme and with financial support from the European Space Agency (ESA), consists of Airbus Defence and Space, AddUp, Cranfield University and Highftech Engineering.

The experiment will use two 3D printers: a ‘flight model’ on the ISS and an ‘engineering model’ on Earth.

Astronauts will print four different samples in orbit to see if prolonged microgravity affects the printing of metallic materials.  These samples will then be sent back to Earth for qualitative analysis: two samples will go to the ESA Technical Centre in the Netherlands (ESTEC), another to the ESA Astronaut Training Centre in Cologne (EAC) for use in the LUNA facility, and the fourth to the Technical University of Denmark (DTU).

Similar samples will be manufactured using the engineering model printer on Earth. At the final stage of the experiment, scientists will conduct mechanical strength and bending tests, as well as microstructural analyses of the parts made in space and compare them with the ‘engineering’ samples.

First 3D Printer Printing In Metal On The ISS

The Metal 3D Printer technology demonstrator was developed by an industrial team led by Airbus, which is also co-funding the project, under contract to ESA’s Human and Robotics Research Directorate.

The printer, weighing around 180kg, is designed to repair or fabricate tools, mounting interfaces, and mechanical parts. It measures 80 x 70 x 40 cm and can print 9 x 5 cm parts from stainless steel wire. One part will take about 40 hours to print.

Challenges Of Metal Printing In Space

Printing metal in space is a complex engineering challenge with technical challenges.

Sébastien Giraud, systems engineer for metal 3D printers at Airbus, explains, ‘The first challenge with this technology demonstrator was size. Today’s metal 3D printers are installed in a laboratory of at least ten square metres on Earth. To create a prototype for the ISS, we had to reduce the printer to the size of a washing machine.’

Equally important is the safety issue: the printer uses a high-energy laser to heat metal and add metal layer by layer to print objects.

The melting point of metal alloys compatible with this process can exceed 1200 °C degrees, compared to around 200 °C for plastic, implying strict temperature control.

This releases vapours that must be controlled with filters and captured inside the machine to prevent them from polluting the air inside the ISS. This creates additional risks for the crew and station equipment.

For safety reasons, the printer operates in a completely sealed box to prevent excess heat or smoke from escaping.

To solve the problem of gravity control, engineers chose a printing technology based on steel wire, which, unlike the powder system, does not depend on gravity.

How The Experiment On The ISS Was Prepared

A flight model of the 3D printer was delivered to the space station in January as part of the NG-20 mission. In May this year, ESA astronaut Andreas Mogensen installed the payload in the European Draw Rack Mark II, part of ESA’s Columbus module.

The printing process began after completing all the necessary commissioning tests, which test the 3D printer’s subsystems and how they work together.

Teams on the ground and in space had to follow a complex operating scenario to reliably manage and control the payload remotely over the ISS telecommunication links.

The 3D Printing Process Was Fully Controlled From Earth

The French space agency CNES controlled the printing operations from their ISS payload control centre. Two operators from Airbus and CNES ensured that the process ran smoothly.

All the crew on board had to do was open the nitrogen and ventilation valve before printing began.

This step required a few adjustments from project partner AddUp. The team was then able to run sequences lasting between two and three minutes.

Before running the following sequence, it was necessary to wait for feedback from the engineers on Earth to check the printing performance and make corrective corrections.

Small Steps Of Daily Improvements

In the first step, the engineers successfully tested the ‘2D’ printing mode – applying a single layer of stainless steel in the shape of the letter S to the moving plate.

The next step was to switch to the ‘3D’ mode, which means applying several layers on top of each other.

Printing each layer was strictly controlled, as each of the 200 layers required controlling the correct height. The height is measured before a calibration command is sent to the printer to adjust the height of the next layer.

Only by mid-July, when 55 layers (half of the first sample) had already been printed, did the printing speed accelerate thanks to optimisation sources on the ground and the ISS. Printing time was increased from 3.5 to 4.5 hours per day.

First Metal 3D Printed In Space

By early August 2024, the first sample was ready.

The metal 3D printer is housed in an airtight box that keeps oxygen levels low. During the printing phase, the oxygen in this box was replaced with nitrogen to protect the ISS and its crew from the risks associated with using a high-powered laser to reach the melting point and prevent metal oxidation.

The final phase of the space experiment involved returning the atmosphere inside the printer to normal so that it could open the sealed box without depressurising it.

On 21 August, astronauts Sunita Williams and Jeanette Epps extracted the first sample from the metal 3D printer.

3D Metal Printing Makes Life Easier For Astronauts

One of ESA’s future development goals is to create a closed-loop economy in space and recycle materials in orbit to enable more efficient resource use, such as repurposing pieces of old satellites into new instruments or structures.

Increasing the duration of future space exploration missions and the distance from Earth will make spacecraft resupply more challenging. Additive manufacturing in space will provide autonomy for the mission and its crew by providing a solution to produce needed parts, repair equipment or build specialised tools on demand during the mission rather than relying on resupply and redundancy.

There are already several plastic 3D printers aboard the ISS, the first of which arrived in 2014. Astronauts have already used them to replace or repair plastic parts, as one of the biggest challenges of daily life in space is supplying equipment that can take months to arrive. But not everything can be made out of plastic.

Gwenael Aridon, lead engineer at Airbus Space Assembly, says: ‘The metal 3D printer will open up new manufacturing opportunities in orbit, including the ability to produce load-bearing structural parts that will be more resilient than the plastic equivalent. Astronauts can directly fabricate tools such as spanners or mounting interfaces that can connect multiple parts. The flexibility and rapid availability of 3D printing in space will greatly improve astronaut autonomy.’